A variety of appliances used in automotive vehicles such as supporting straps, glove box lids, asher tray covers or the like are actuated by spring means. Supporting straps, for example, are returned by springs to their basic or normal position. Glove box lids are brought to the open position after manually releasing a locking means. The travel of the movable elements is stopped by impacting a stop. This results in a more or less loud noise; moreover, there is no smooth motion and possibly there might be a swinging back or rebound of the appliance element after stopping. Accordingly, dampening means are known providing for a more or less dampened motion in approaching the end stop.
German utility model 87 07 936 discloses a so-called rotary damper comprising a shaft having a radial vane disposed within a chamber filled with a liquid fluid such that the fluid is displaced from one chamber section through a throttle passage into another chamber section when the vane is rotated towards either one of two radial stops spaced peripherally with respect to each other. The throttle passage may be defined by a gap between the vane and the inner wall of the housing as disclosed in DE 33 16 756. Alternatively, or in addition, the vane may be provided with at least one opening through which the viscous fluid passes.
DE 39 21 326 discloses a disk-shaped rotor which is centrally located in a hollow space provided by the housing, all surfaces of the rotor being in contact with the viscous fluid.
The braking torque generated by a rotary damper of this type depends of course on the size of the surface of the rotor and housing disposed in contact with the viscous fluid. Thus, the torque increases when the dimensions of these elements are made larger. However, in many cases it is desired to build a rotary damper of this type as small as possible.